Fire doors find applications in a variety of commercial settings, including within critical national infrastructure projects across the country. But how are they made, how are they tested, and what kind of regulations do manufacturers need to adhere to? The team answers these questions, and more, below.
There are a variety of test standards for fire doors, depending on the doors’ intended use and the geographical location around the world, although we typically design and test to EN 1634-1. These test standards require sample doors to be mounted within the wall of a furnace and exposed to temperatures typically in the range of 1000°C to 1300°C for periods of up to four hours.
Whilst we do supply fire doors for use within commercial environments, they are also supplied for use within a wide variety of locations where a threat from fire has to be contained, such as transport infrastructure, test facilities, utility infrastructure, and production and processing facilities.
There are many types of fire door test standards in use around the world, some of which are country specific, and others which are industry specific.
At Rhino Doors, we typically use the European standard EN 1634-1 for testing, although in some circumstances it is still acceptable to use the older British Standard, BS 476 Part 22.
Doors for North America (or countries adopting North American standards) are tested to UL standards or NFPA 252. Fire doors used on offshore oil rigs are typically tested to International Maritime Organisation (IMO) standards.
All of these standards require the door to prevent the passage of the fire (known as an integrity rating) but may also require limits on the temperature of the door on its unexposed (or ‘cold’) side. This aspect of fire door performance is achieved through the use of insulating material in the door leaf. This can be required where there is a risk that radiated heat from the door containing the fire might ignite other elements on the safe side of the door, or that radiated heat might hamper personnel evacuating a building via a passage on the safe side of the door.
Unlike blast doors, which often have their performance proven by calculation, all fire doors must be proven effective by means of a physical fire test – or, in special circumstances, performance may be based upon previous tests and a technical assessment by a suitably qualified body.
Test doors are mounted in a test furnace which then increases the furnace temperature and pressure according to a profile determined by the relevant standard. During the test period, test engineers will closely monitor the performance of the door, observing any integrity failures, as well as recording deflection of the doors. In the case of insulated doors, they will also measure radiated heat and cold-face temperatures of the leaf and frame.
Test furnaces can be up to 8 m wide x 5 m high to accommodate the testing of particularly large doors. During testing, uninsulated doors glow red and radiate large amounts of heat into the test facility.
Some tests also require that a powerful water hose be played onto the face of the door which has been exposed to the furnace at the completion of the test. This is to check that the door can still withstand physical forces even after it has been exposed to temperatures of 1000°C + for well over an hour.
The doors tested must incorporate all of the elements that will be included within the doors supplied to a project and must therefore incorporate features such as vision panels and specific items of hardware.
The construction of the door will vary depending on the applicable test standard, differences in the door leaf skin thickness and depth, the internal construction of the door leaf – which may incorporate an insulation material – and the latch and hinge system which holds the leaf in the door frame.
Under the EN 1634-1 standard that Rhino typically uses, successfully tested doors are assigned a series of letters and then a number, where:
For example, an EI120 door is one with both integrity and insulation ratings for up to 120 minutes, or 2 hours. An E240 door has an integrity rating only for 240 minutes, or 4 hours. Note that insulated doors must maintain their integrity for the same period of time as the insulation – i.e. it is not possible to have an insulation-only rated door.
As a further refinement, EN 1634-1 doors that have an insulation rating will sometimes be recorded with a suffix 1 or 2 after the EI element of the code, e.g. EI2120. This suffix is used to indicate where the thermocouples on the cold face of the leaf are positioned, relative to the frame fixed to the wall. A suffix ‘1’ means that the thermocouples are placed closer to the wall frame which means they are likely to heat up quicker – therefore a more onerous test.
Test standards are updated or replaced on a periodic basis to ensure that they accurately reflect the effects of full-scale fires and to ensure that the products tested provide an adequate level of protection against those fire effects. This means that product development and re-testing has to be performed on a regular basis.
All fire doors must be regularly maintained in accordance with the manufacturer’s requirements to ensure that they continue to provide protection against the threat of fire. There is no point in having a normally held open fire door if it does not automatically self-close when a fire occurs.
The design and construction of the door will reflect the specified design life, which can typically be anywhere from 15 years to 35+ years.
There’s a lot to consider when investing in a fire door, especially with a range of different specifications and ratings available, depending on their intended use and installation location. As a leading fire door manufacturer, our team has a wealth of knowledge. We hope this Q&A has been useful, answering any questions you may have about our products. For more information, click here to read our fire door case study.